Telephone system



'C. L. GOODRUM. TELEPHONE SYSTEM. APPLICATION FILED FEB.26, 191s;

Patented Apr. 20, 1920.

2 SHEETSSHEET l- /n van for: C/mr/es L. Good/um. y

C. L. GOODRUM. TELEPHONE SYSTEM. APPLICATION FILED FEB. 26, 1916.

2 SHEETS-SHEET 2.

Patented Apr. 20, 1920.

//7 van for: Char/e8 L. 600 drum. by

UNITED STATES FATENT OFFICE.

CHARLES GOODRTTM, OF NEW YORK, N. Y., .ASSIGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Apr. 20, 1920.

Application filed February 26, 1916. Serial No. 80,690.

To all whom it may concern:

Be it known that I, CHARLES L. GooDRUM, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and usefullmprovements in Telephone Systems,of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems in which connections fromcalling to called subscribers lines are established by means ofautomatic or electrically operated switching devices.

The principal feature of this invention resides in the provision ofmeans whereby a plurality of brush sets, which are provided as terminalsof the same telephone circuit and are carried on the same movable switchelement, are employed in simultaneously hunting for a desired line.

A further feature of the invention resides in the provision of meanswhereby the brush set which first engages the terminal to a desiredl'newill be definitely associated with the tele hone circuit of which it isa terminal, and the remaining brushes will be maintained disconnectedfrom said telephone circuit.

The present invention may be employed to decrease the time necessary tofind and make connection to desired lines,or in certain'instances may beemployed to increase the size of line groups. It may be used withswitches arranged either to find and make connection to callingsubscribers lines, or to find and make connection to idle trunk lines.In the present disclosure the invention is shown as applied to ajlinefinder switch, and to a trunk selecting switch. I

Referring to the drawings, Figures 1 and 2 with @Fig. 1 at the leftdiagrammatically indicate the apparatus and circuits employed in thepresent embodiment of the invention. Theswitch herein disclosed may beof the characterof that shown in patent to Oscar l1. Forsberg, No.1,252,420, issued January 8, 1918, although obviously any switch whichhas a set of movable brushes may be employed. In the switch of theForsberg application above referred to ten brush sets are shown, theseveral sets being spirally arranged about 'the shaft. A separate groupof terminals is provided for each brush set, and the appropriate brushis brought into operative engagement with its particular series ofcontacts by rotating the supporting shaft.

As a series of ten contacts is provided for each of the brushes, theswitch will have a capacity of 100 lines, In the present disclosure thenumber of brushes may bedoubled, or the number of rotary positions maybemade one half the number of the Forsberg switch. Whichever structure isemployed, the sets of brushes will be arranged in pairs as 2-2, 33'.etc. The sets of brushes of each pair are arranged in alrnement, but theseveral pairs of sets are spirally arranged about the shaft. In case itis desired to employ the present invention to decrease the length of thehunting operation, but five contacts would be arranged in the seriesprovided for each of the brush sets. and, if the number of rotarypositions of the switch are decreased, it would result .in doubling thesize of the line groups. In

the first instance only five vertical steps of the switch would berequired in finding the last line of a group, whereas in the secondassumption, while the number of steps, that is ten, for finding the lastline would be the same, the size of the group would be doubled.

In the present disclosure the desired sets of brushes will also bebrought into operative relation with their respective groups ofterminals by rotary movement of the shaft 1. This rotary movement willbe accomplished by means of the stepping magnet 5, to the armature 6 ofwhich, is secured the stepping pawl 7. The pawl 7 is arranged tooperatively engage the ratchet wheel 8 fixed to the rotatable shaft 9.Thespur gear 10 is also fixed to the shaft 9, and

when thebrush shaft 1 is in its lowermost position, gear 10 operativelyengages the gear 11 fixed to shaft 1 near the lower end thereof. Thecoil spring 12 has its inner end secured to the shaft 9, and its outerend secured to the framework in any desired manner. Retrograde movementof the shaft 9 is prevented by means of the pawl 13, which projects fromthe yoke 14 p votally supported on the pin 15. Thus it will be seen thatof the ratchet wheel 8 will be communicated to the shaft 1 so that adifferent pair of brush sets 2-2, 3-3, etc., will be brought intooperative relation to their respective the step-by-step rotary movementcontact groups upon each energization of the magnet 5.

The vertical movement of the shaft 1 is caused by the magnet 16, thearmature 17 of which is provided with a pawl 18, which is arranged tocooperate with the circular ratchet teeth 19 on the shaft 1 to move thebrushes from set to set of contacts upon successive energizations of themagnet 16. Downward movement of the shaft 1 is prevented by means of thepawl 20, which is carried by the yoke 21 pivotally mounted on the pin15.

At the lower end of the shaft 1 is a spring detent 22, which, upon thefirst upward step of the shaft 1, is released and operatively engagesthe gear wheel 10. The release and return to normal of the switch iscontrolled-by the magnet 23, the armature 24; of which is fixed .to theyoke 14, which carries the pawl 13. The yoke 14 isprovided with a finger25, so positioned adjacent to the finger 26 of the yoke 21 that, uponthe attraction of 20, as well as the pawl 13, is retracted. The

reverse rotary movement of the shaft 9 at this time is prevented,however, by means of the detent 22, and the shaft 1 is maintained in adefinite rotary position by the engagement of the brushes with thecontacts. As the shaft 1 approaches its normal position, the gear '11drops into mesh with the gear 10. At the same timethe detent 22 isretracted, and the switch is rotated to its normal position by means ofthe spring 12.

It is to be understood that the invention is not limited to employmentwith a switch of the type herein disclosed, as any other two movementswitch, or in fact any other switch which is provided with progressivelymovable brushes, may be employed with the present invention.

The circuit changing device or side switch herein disclosed may besimilar in character to that shown in the patent to Keith and EricksonNo. 815,176 of March 13, 1906. The switch shown in this patent, however,will not operate in a manner necessary to fulfil the requirements of thepresent invention. A circuit controlling switch, such as employedherein, is shown in the above noted application to Oscar F. Forsberg.This side switch may be caused to move its wipers either upon theenergization or upon the deenergization of its controlling magnet. Thisis accomplished by the omission from its escape wheel of the appropriateratchet teeth.

the armature 24, the pawl terminates at the same time that the brushes2' are passing over the contacts of the group in which the line Aterminates. It will be further noted that only one connecting circuit ortrunk is provided for the sets of brushes 2 and 2', the set of brusheswhich is operatively connected to said trunk being determined by theenergized or deenergized condition of the auxiliary test relay 27 Thebrushes 2 are normally connected to the trunk, but upon the energizationof the relay- 27 the'brushes 2 are cut oif and the brushes 2are'connected to the trunk instead. It is to be understood that aplurality or group of lineifinder switches will be employed in thepresent invention in a manner similar to that disclosed in applicantsapplication, Serial N 0. 35,326, filed June 21, 1915.-

It is believed that the invention will now be readily understood'from adescription of the manner in which the switches operate in'establishi nga connectio Assuming now that the subscriber having the line A initiatesa call by removing his receiver from its hook; this will complete acircuit from battery through the left winding of line relay 28,back'contact and left armature of cut off relay 29 over the lower sideof the subscribers line A, through the substation thereof, over theupper side. of the line At, through the right armature and back contactof relay 29 and the right winding of relay 28 back to batt'ery. Relay 28attracts its armatures andputs potential on the right terminal of theset in which line A terminates, from the source'of current 30, throughtest relay 31, right contact and armature of relay 28. It alsofig-{completes a circuit from battery through relay 32, back contact andleft armature of relay 33, left armature and contact of relay 31, leftcontact and armature of relay 28 and the right Winding of relay 28 toground. Relay 32 is energized and locks up through its left armature andcontact.

net 5 is repeatedly energized and deenergized, thus stepping the sets ofbrushes 2-2', 23-3, etc., successively into operative relation to theirrows of contacts, until the brush 36 carried at the top of the shaft 1engages the contact 37 individual to the group of the calling line. Acircuit will now be completed from battery through the escape magnet 38,side switch wiper 39, brush contact 37, outermost right armature andvcontact of relay 32 and the right armature 30 rupted, stopping thevertical stepping acand contact of relay 31 to ground. Escape magnet 38will be energized and will'move the side switch wipers to osition 2.

In position 2 a circuit is completed from battery through the verticalstepping magnet 16, its individual interrupter contact 4 side switchwiper 35, relay 33, innermost right armature and front "contact of relay32, and right armature and contact of relay 31 to ground.' Due to theaction of the individual interrupter 40, magnet 16 will be repeatedlyenergized and deenergized, thus stepping the sets of brushes 2 and 2from set to set in their respective series of contacts. When the brushes2' engage the contacts of the line A, a circuit will be completed fromsource of current 30, through test relay 31, contact and right armatureof line relay 28, right contact and right brush 2, through condenser 41,side switch wiper 42, auxiliary test relay 27 tobattery and 1 ground.This will cause an impulse of current to pass through relays 31 and 127,and

both will attract their armatures. During the vertical steppingoperation a circuit extend ed through escape magnet 38 and side switchwiper 39 in parallel with the vertical magnet 16 and wiper 35. Now, uponthe attraction of the armature of relay 31,. the circuit for magnets 16and 38 will be intertion and causing the de'nergization of the escapemagnet 38, whicln'upon the retrac tion of 1ts armature, moves the sideswitch wipers to position 3. When the side switch goes to position 3,relay 27 is locked up by a circuit through its upper armature andcontact and side switch wiper 42, which.

locking circuit will be maintained until the side switch is restored toits normal position upon restoration of the switch.

Had the subscriber of line A initiated the call instead of thesubscriber of line A, the operation would have been exactly the same asjust described, with the exception that the test circuit would haveextended from the source of chrrent 30, through relay 31, contact andright armature of the line relay 28'- of line A to the right contact andthe right brush 2. through the innermost lower armature and back contactof relay 27, wiper 43. condenser 44, resistance 45 to battery andground. Relay 31 would have been energized and accomplished the samefunctions as previously described. As the side switch would move toposition 3 immediately after the test, the energizing circuit for therelay 27 would be open, thus insuring that the lower armatu'res of thisrelay wouldremain retracted and thus maintain the brushes of the set 2connected to the trunk. r

' As the side switch" moves to position 3, the starter wire 46 isextended through the back contact and innermost right armature of releftbrush of the set 2 and the winding of the cutoff relay 29, to ground. eRelay 29 will be energized, thus interrupting the circuit of line relay28, which, in retracting its ar-" matures, will return the commonmechanism to its normal position.

In position 3 of the side switch, the side switch wipers 43 and 47 alsoextend the calling line through to the selector switch shown in Fig. 2.I

The calling subscriber may now operate his 'dial to send a series ofimpulses to the selector switch shown in Fig. 2. This switch may be ofthe same structure as that indicated in Fig. 1. Whenside switch wiper 43reached its third position a circuit was completed from battery throughthe right winding of trunk relay 48, side switch wiper 49, the leftWinding of relay 48, Wiper 43, innermost lower armature and frontcontact of relay 27 right brush 2, the line terminal engaged thereby, frontcontact and.

right armature of cutoff relay 29 over the upper side of' thesubscribers line A, through the substation thereof, back over the lowerside of the subscribers line, through the left armature and frontcontact of relay 29, and through the winding of relay 29 to ground. Thiscircuit causes the energization of relay 48, which in attracting itsarmature completes a circuit from battery, through the winding of relay50, front contact and armature of relay 48, back contact and armature ofrelay 51, back contact and armature of release magnet 52 to ground. Thesubscriber now sends the se lecting series of impulses to operate theswitch shown inFig. 2. The sending device may be of any desired andwell-known construction which operates to produce a series ofinterruptions in the line circuit. With each interruption at the sendingdevice, the circuit of relay 48 will be broken and it will retract itsarmature, completing a circuit from battery, through the rotary steppingmagnet 53, side switch wiper 54, and also from battery through theescape magnet relay 55 in parallel with magnet 53, and thence throughthe front contact and innermost armature of relay 50, back contact andarmature of relay 48, back contact and armature of relay 51 to ground,through the back contact and armature of release magnet 52. Relay 55, inattracting its armature,.will cause the energization of theesenergization of relay 18, the rotary stepping magnet 53 w1ll berepeatedly operated to step the switch shaft 57 of the selector switcharound until the sets of brushes 58 In position 2a circuit is completedfrom battery through the "ertical stepping magnet'59, its individualinterrupter 60, wiper 61, front contact and armature of relay 48, backcontact and armature of relay 51 and back contact and armature ofrelease magnet 52 to ground. It is to be understood that the testcontact of idle trunks, that is, the right or under contact in Fig. 2,will be connected to ground throu h a resistance in any well-knownmanner. his ground connection may for example be made through a backcontact of the first slow relay corresponding to relay 50. As this relayholds its armatures continuously attracted whenever its switch is inuse, the ground is present on the test contact only when the switch isidle. We will first assume that the brushes 58 are first to engagethecontacts of an idle trunk. When this occurs, a circuit will becompleted from battery, through the auxiliary test relay 62, the normallower contacts of this relay, the right brush of the set 58 and thecontact engaged thereby to ground through resistance 63. Relay 62, inattracting its lower armature, will complete a locking circuit foritself, which extends to ground through the front contact and outermostarmature of relay 50. In attracting its innermost upper armature, itcompletes a circuit from battery through the test relay 51, innermostupper armature and front contact of relay 62, right brush of the set 58and the terminal engaged thereby, to ground through resistance 63. Relay51 in attracting its armature, will complete a circuit from batterythrough the escape magnet 56, front contact and armature of relay 51 andthe back contact and armature of release magnet 52 to ground. Magnet 56will be energized and move the side switch wipers to position 3.

At the time test relay 51 is energized the line relay and consequentlythe first slow relay at the second selector switch will also beenergized which will operate to remove the ground from the test contactengaged by the right brush of the set 58, thus causing the immediateretraction of the armature of relay 51. As the relay 50 is slow torelease,

62. In thecase now it will not drop off its armature during themomentary interruption of its circuit at the back contact of relay 51.

Had it happened that the calling line terminated in the series of'contacts traversed by the set of brushes 58, the operation would havebeen the same as justdescribed with the exception that the operation ofthe test relay 51'would not have been preceded I by the operation of theauxiliary test relay assumed, the operating circuit for the relay 51would extend from battery through said relay 51, the innermost upperarmature and back contact of relay 62, the right brush 58 and thecontact engaged thereby, to ground through the resistance 63. Thus itwill be seen that, irrespective of which brush first engages an idletrunk, the switch will be stopped with said brush on the contacts ofsaid trunk and the set of brushes on the idle trunk will be connected tothe trunk circuit, the other'set of brushes being maintaineddisconnected from the trunk circuit.

As the side switch of the selector moves to position 3, thecircuitextending through the right winding of relay 48 will be interrupted, butas battery will be supplied at this time from the next selector switchto the contact engaged by the left brush 58 or 58, depending upon whichhas first found the idle trunk, this relay will not retract itsarmature, as a circuit will now exist from battery-through the leftbrush of the operative set to the uppermost armature of relay 62, wiper49, left winding of relay 48, wiper 7 43, innermost lower armature andfront contact of relay 27, the right brush of the set 2 and the contactengaged, the front contact and'right armature of relay 29, the upperside of the subscribers line A through the substation thereof, back overthe lower side of the line A through the left armature and front contactof relay 29, to ground through the winding of relay 29.

The release of the line finder and the first selector switches at thetermination of the conversation is controlled at the back contact andoutermost armature of relay 50.

When the calling subscriber replaces his receiver upon the hook, theabove traced C11- cuit through the left winding of relay 48 isinterrupted and it retracts its armature, thus permanently opening thecircuit for the relay 50 which in turn becomes denergized and completesa circuit from battery throng 1 the release, magnet 23 of the linefinder switch, back contact and right armature of relay 33 and frombattery through the release magnet 52 and off-normal contact 64 andthence to ground through the back contact and outermost armature ofrelay50. The release magnet 23 thereupon locks up through a circuit includingoff-normal contact 65 and the contact 66, and remains said series oflocked until contact 65 is opened as the switch reaches its normalposition, litelease magnet 52 also looks upthrough oilnormal contact 64and its armature and front contact, thus insuring the full return tonormal oi the selector switch.

It will thus be seen that the arrangement herein disclosed providesmeans whereby two sets of brushes may each hunt over their respectiveseries of contacts at the same time and whereby the brush set, whichfirst engages the contacts of the desired line, will be maintained inengagement with said confacts and will also be connected to the trunkcircuit, the other set of brushes being maintained disconnected from thetrunk circuit. While the invention herein disclosed is applied to atwo-wire multiple system, it is obvious that it is equally applicable tosystems of other characters and that other means than those disclosedherein may be employed for determining which of the brush sets will beconnected to the trunk circuit.

What is claimed is:

1. In a telephone system, a switch including a plurality of brushes,series of circuit terminal contacts, one for each of said brushes, eachseries being the terminals of a different group of circuits, automaticmeans for simultaneously moving said brushes over contacts, and a singletest relay for stopping the movement of said switch when any one of saidbrushes engages the contact of a desired circuit.

2. In a telephone system, a switch including a plurality of brushes,series of circuit terminal contacts, one for each of said brushes, saidseries being the terminals of different groups, automatic means for simultaneously moving said brushes over said series oft contacts, a testrelay, a circuit for said relay having branches including said saidcircuit when any one of said brushes, respectively and means for closingbrushes engages a desired circuit terminal.

3. in telephone system, a switch including a plurality of sets ofbrushes, series of circuit terminal contacts, one for each of said setsof brushes, a telephone circuit, a single relay for joining said circuitto one or another of said brush sets, automatic means for simultaneouslymoving said brush sets over their series of contacts, and means operatedwhen one or the other of said brush sets engages the contacts of adesired circuit for stopping the movement of said switch and joining theengaged brushes to said telephone circuit.

4,. In a telephone system, a switch including a air of brushes, atelephone circuit, a relay or connecting one or the other of saidbrushes to said circuit, a series of line terminal contacts, one foreach of saidbrushes, automatic means for simultaneously moving saidbrushes over said series of contacts, and

ing a pair of brushes,

means controlling the operation. of said relay whereby the brush whichfirst engages the contact of a desired line will e connected to saidtelephone circuit,

5. in a telephone system, an electrically phone lines terminating insaid series or contacts respecti ely, means 'ierat on the initiation ofa call on one of said lines for automatically and Sil'lilf" neously inovin said brushes over said series of contacts, an a single test relay tostopping the move ment of said switch when any one oi? said brushesengages the contact a calling line,

7. in a telephone system, a switch includ in a plurality of brushes,series oi contacts, one for each of said brushes, telephone linesterminating in said contacts respectively, means actuated upon theinitiation of a call on one of said lines for automatically andsimultaneously moving said brushes over said contacts, a test relay forstopping the movement of: said switch, a circuit for said relay havingbranches including said brushes respectively and the-contacts of saidseries and means for closing said circuit when any one of said brushesengages de sired line terminal,

7-8. In a telephone system, a switch includseries of contacts, one foreach of said brushes, terminating in said contacts respectively, atelephone circuit, a relay for. connecting one or the other of saidbrushes to circu means responsive to the in 'ation of a call. on 'one ofsaid lines automatically and simultaneously moving said brushes oversaid series of contacts, and neans control.- ling the operation of saidrelay whereby when. one or the other of said brushes en:

gages the contact said calling line, sic.

brush will be connected to said telephone circuit/ 7 7 9, In a telephonesystem, a switch having a plurality of brushes, series of contacts onetacts, and a single test relay for stopping the movement of said switchwhen any one ill:

of said brushes engages the contact of an" idle trunk.

10. In a telephone system, a switch .having a plurality of brushes,series of contacts one for each of said brushes, trunk lines pletingsaid circuit through any one of said brushes and the contact of thefirst encountered idle trunk.

11. In a telephone system, a switch having a pair of brushes, series ofcontacts one for each of said-brushes, trunk lines, terminating in saidcontacts respectively, a telephone circuit, a relay for connecting oneor the other of said brushes to said circuit, automatic means forsimultaneously moving said brushes over said contacts, and meanscontrolling the operation of said relay whereby when one or the other ofsaid brushes engages thecontact of an idle trunk, said" brush will beconnected to said telephone circuit. i

12. In a telephone system, an electrically operated switch having twobrushes, series of contacts one for eachof said brushes,

trunk-lines terminating in said contacts re-,

spectively, automatic means for simultaneously moving said ,brushes oversaidcontacts, a telephone circuit, a test relay for stopping themovement of. said switch, a circuit for said relay having alternativebranches extending through said brushes respectively, and a secondrelay, said second relay being operative to control the extension ofsaid test circuit to the brush which first engages the contact of anidle trunk and to operatively associate said brush with said telephonecircuit.

In witness whereof, I hereunto subscribe my name this th day of FebruaryA. D.,

CHARLES L. GOODRUM.

